[Ducati] 749 sputters and coughs passing from 4500-6800 rpm

[Wendell S. Martin]

The bike 06' 749 is running great except for this problem.   If you go
through this range (4500-6800) at a "slower" acceleration, it does
nothing wrong.  But, the greater the acceleration, the greater the
sputtering and coughing.  I have put new plugs in.  By the way, I can
not find even a reference on Google for these RG59V  champion plugs.  I
had to resort to NGK's.  Where can I buy this champion plug.  I am 200
miles from nearest dealer.  What have we to speak to on this mystery
sages.  And please help me. Can someone please explain the theory of
operation of the "TPS".  I know that it communicates to the ECU the
position of the throttle.  Is it a digital device?  
Thanks
Wendell